Crate resamplescope 

Reverse-engineer the resampling filter used by any image resizer.

Port of ResampleScope by Jason Summers (~1400 lines of C, GPL-3.0-or-later). The original tool generates test PNG images, has the resizer process them externally, then reconstructs the filter kernel shape from the output.

This port replaces that file-based workflow with a callback API: you provide a resize closure, and the crate handles everything in-memory. It adds scoring against reference filters, SSIM comparison against perfect reference weight tables, and edge handling detection.

License

AGPL-3.0-or-later. See LICENSE.

Original work

• Author: Jason Summers
• Website: http://entropymine.com/resamplescope/
• License: GPL-3.0-or-later

This crate is a derivative work. The test pattern generation and filter reconstruction algorithms are ported from the original C source.

Filter implementations

The reference filter math in filters and the separable 2D resize in [reference] use standard mathematical definitions (sinc, Mitchell-Netravali, etc.) and standard resampling algorithms. The authoritative, optimized implementations of these filters live in imageflow by Imazen.

Re-exports

pub use analyze::FilterCurve;

pub use edge::EdgeMode;

pub use filters::KnownFilter;

pub use reference::PixelWeights;

pub use reference::WeightEntry;

pub use score::FilterScore;

pub use pattern::generate_dot_pattern;

pub use pattern::generate_line_pattern;

pub use reference::compute_weights;

pub use reference::perfect_resize;

pub use score::ssim;

Modules

analyze

edge

filters

graph

pattern

reference

score

Structs

AnalysisConfig

Configuration for analysis.

AnalysisResult

Complete analysis result from probing a resizer.

Enums

Error

Error type for analysis operations.

Functions

analyze

Run both downscale and upscale analysis, score against known filters, and optionally detect edge handling.

analyze_downscale

Run only the downscale analysis (dot pattern, 557->555).

analyze_upscale

Run only the upscale analysis (line pattern, 15->555).

Type Aliases

ResizeFn

The resize callback type: takes a grayscale source image and target dimensions, returns the resized grayscale image.